Structure-property relations and the design of Fe-4Cr-C base structural steels for high strength and toughness |
| |
Authors: | B V Narasimha Rao G Thomas |
| |
Affiliation: | (1) Analytical Chemistry Department, Research Laboratories, General Motors Technical Center, 48090 Warren, Michigan;(2) Materials and Molecular Research Division, Lawrence Berkeley Laboratory, USA;(3) Department of Materials Science and Mineral Engineering, University of California, 94720 Berkeley, CA |
| |
Abstract: | Some design guidelines for improving strength-toughness combinations in medium car-bon structural steels are critically reviewed.
From this, quaternary alloy development based on Fe/Cr/C steels with Mn or Ni additions for improved properties is described.
Transmission electron microscopy and X-ray analysis reveal increasing amounts of retained austenite in these alloys with Mn
content up to 2 wt pct and Ni additions at 5 wt pct after quenching from 1100°C. A corresponding improvement in toughness
properties is also found. Grain refining results in a further increase in the amount of retained austenite. In addition, the
excellent combinations of strength and toughness in these quaternary alloys are attributed to the production of dislocated
lath martensite from a homogeneous austenite phase free from undissolved alloy carbides. The question of thermal instability
of retained austenite following tempering is considered in detail and it is shown that the decomposition of retained austenite
is closely related to the ease of nucleation and growth of cementite. Thus, graphitizing alloying elements such as Ni are
beneficial in postponing the decomposition of retained austenite.
Formerly with the Lawrence Berkeley Laboratory, Berkeley, CA
This paper is based on a presentation made at a symposium on “Precipitation Processes in Structural Steels” held at the annual
meeting of the AIME, Denver, Colorado, February 27 to 28, 1978, under the sponsorship of the Ferrous Metal-lurgy Committee
of The Metallurgical Society of AIME. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|